Float structure



Dec. ,8, l925- n 1,564,826

' R. cHlLToNE-r Al.

FLOAT STRUCTURE I Filed Mrcn 1e, 1925 s sheets-snee; 1

1925 I 3 Sheets-Sheet 2 @nvm TTUR/VEY R. CHILTONTT AL FLOAT STRUCTUREFiled March 16 be@ s, 1925.

3 Sheets-Sheet 3 R. CHILTON Er AL FLOAT STRUCTURE Filed March 16. 1925 wQ w MM5 8. s D

Passes neas, 1925.

.Nrrao s'rATEs price. f

:ROLAND CHILTON @AND FRANK Lunnis, or xEYronT, NEW' cansar, AssIeNons To.assomme PLANE a -uoTon comumxr,- INC., a coaronATIoN or New Yoan.

FLoaT STRUCTURE.

Application mea :man is, 1925. serial No. 15,1985.

To all whom it may concern.' v

Be it known that we, ROLAND CHILTON, a subject of 1 the King FRANK A.HAYES, a citizen lof the United States, and both residents of Keyport,in the countyofMomnouth vand State of New Jersey,'have invented certainnew and useful improvements in Float Structures, of which the'following`is a specification, reference being had to the accompanying drawings,forming part of this specication.

This invention relates to hulls in general and especially to 'closedoats or pontoons as used on hydroplanes. The invention provides, in aspecic aspect, im roved structure and methods of fabricatlonrfor. metalfloats such as have been previously made by applying very light platesto a framework vcom rising4 a series of transverse frames an bulkheadsdefining the athwartships proles and secured tojke'elsons and otherlongitudinal members. l

Such light metal structuresV are characterized by the very great numberor'l rivetsl required to obtain adequate strength and water-tightness.With conventional constructions, and especially Yin small watertightcompartments,.the rivets for the as-v scmbly of the last plates can onlybe vreached through hand holes 'which make the setting of many rivets anawkward and laborious i hand operation, and this is the chief .cause ofthe 'excessivecosts of this type of construction, especiallywherewater-tight packing has to be fitted with each joint. The

metal construction, however, is greatly to v be desired on the groundsof strength, lightness and durability., 1

One of the prime ob]ects of this invention accordingly, 1s to provide anew type of' construction wher-ein all rivets"`w`i1l be easy of accessand whereby the great majority may be driven with the float in opencondition. l

To this cnd the fabrication of the float in two longitudinal halves has1-1.- and essential features of Athis invention reside in thedevisingiof a structural system which will render this two-part'fabrication practicableV 'and which will provide means whereby thehalves may be-.united by-relatively `few, and these 'readily accessible,rivets. For instance, in the conventional construction a large number ofathwartshp floor-beams are usually each securedby a of England, and.

, ing flange v on Ythe other.

. multiplicit of rivets to opposite-sides bf the web o a central keelsonto which transverse` bulkheads-mustconform and be securedv in-'awater-tight manner. Further, the bulkheads must be made water-tight tothe skin around the ,v entire periphery and the rivets involved couldnot be driven after the two halves,l with the skin in placeha`ld beenbroughttogether, since these'pontoons are in general too small to permitof la mechanic getting inside.

Accordingly, this invention provides a hollow keelson made in twohalves, one f which is completely riveted to the loor beam ends of eachalf before the halves are brought-together and therefore'while everyrivet is completely accessible through the (then open)4 entireinboa'rd'profile of the float. l

Upon final assembly a downwardly open space is left between the sides of-this keelson whilst' a horizontal flangev extendingV along the top ofone half la s a correspond- .bese dan esi are directly under a centralopening 1n the deck and are accordingl easily accessible for riveting byv wor in respectively through that opening and gram.. below.

This hollow keelson a'ords'a ready means to receive a detachable keelorrubbing strip, `preferably of -wood,which may have -relad tively greatdepth to take shock loads, as

when handling theJ `ship on shore, andv yet which does not pro]ect farenough tov be liable to sideways failure.

Floats such as here described often support an aeroplane through strutsat the amidships sections and are accordingly subject to lgreatlongitudinal bending moments. With the dept between top and bottomplates usual to these closed float profiles, it will' be vfound thatthe'thinnest practicable plates,

considered as a tubular beam Agive the structure much greater strengthagainst longitu- 'dinal bending than would any lpracticable keelsonstructure. The side walls of the loat thenact as shear members,distributlocal crumpling is prevented by p suitable vstil'eningy andbracing means. The usual thwartships curvature of the deck is ofassistance 1n this direction, and this invention proposes an improvedbracing means; for

.the oor which also connects to vthedeck to` prevent lateraldistdrtionsthereof.

The skin system of support outlined above involves the carrying of allloads and l reaction into the side walls, as should be done' areoftenused as a beam between -bulkheadsl in all'` thin' flanged beams,since the thin flanges have vby themselvesv very little resistance tolateral loads. o i

The function of the floor .cross beams 1s to carry the supporting waterpressure on the i bottom plates to the sidewalls, tovwhich the outboardends of the cross beams are accordingly tied` over a suflicient area. todevelop adequate strength in the plate. The length of these beamscorresponds. to the ,width of ,the float and under the uniform waterloading the required strength increases as the square ofgthis dimension.Heavy keelsons to relieve the cross beams ofsome portion of the load onthe center of their span. The

load distribution in such constructions is only determinable aftersuccessful analysis of the relative stiffness of. the loor and keelsonbeams.

In accordance with theI loi-part structure of this invention, the floorbeams are definitely designed as half width members and I' the entirekeel-end loads are transferred to the side walls by a new bracestructure constitilting-the basis of-each athwartship frame andcomprising central king-posts from the top of whichdiagonal ties connectto the si e wall' and outboard end ofthe cross beams. l As statedabove,` these king posts tie into the deck while the tension memberconverts the curved deckfplates andstieners into abowstring Aarchedstructure thusfgivinggreat resistance against lateral distortion andsecondary failure, without .any added weight. It will be appreciatedthat this trussed structure reduces the eective span of the floor beamsby .one half and consequently the'bending load on, and the weigth of,.lhese` l,arts to rone-fourth. Hence the truss utilizin the lentire deth of the float 4affords .a lig ter structure t an the usualHange-a-nd-web beams bridging.v

the entirewidth of the ioat. v

It will bej seen that the strength of the structuregas' ap'whole de endsupon the refy sistance to llongitudine extension of lthe `vdeck andbottom plates. The continuity of the latter isv usuallyr interrupted bythe amidships step Yby which the bottom prolels broken. Another featureof this iny lvention resides in. the construction which developsconsistent stren th along the whole .of the .bottom plates espite t esteps.- `Accordlng to this system lthe after (and upper) bottom platesare carried forward over Leejaeae thefstep and trend downwardly to anattachment with. the forward bottom plates,

whichextend aft of this connection to form' .i

the step, whereat the whole structure is suitably reinforced as by a'transverse beam having its upper flange secured to the after plate. Thegreatest impact. to which the bottom plates are subject occur justforward of the step and in the construction of thisinvention thestructure is of box form at this part and 'is accordingly especially fstrong. v

` The bottom of the-floats for hydreplanes are subject to severe waterimpact loads in landing. and takin 0H at high speeds in rough waterwhilet e side 'plates in general only receive the very much smaller hydro-.,static pressure due to their depth of immer-- sion. In usualconstructions, built up around pre-formed thwartship profile frames, thefloor beam and deck stiener members have the same-longitudinal spacing,which is not consistent with the large difference of loads on the-twoareas. v

Upon analyzing the support of a plate, under a specified loading, bycrossv beams., it will be found that the total wei ht of beams (of acertain heightyis indepen ent of y the number of beams used, i. e.,independent of the beam spacing. Doubling thenumber of beams in a givenlength merely results in halving the load on,1and therefore thenecessary weight of, each.-` On the contrary, con-` floor beam anddecklframe `usually employed, such close spacing of .the floor beamswould lead to an unduemultiplicity of deck frames and this inventionaccordingly includes 'inter-costal `floor cross beams adequately tied attheir ends to the keelson and.

side walls respectively. y i To further carry outthe object of ail'ord'ing complete accessibilityV of all parts of the internal structure,-`longitudinal openings` with removable cover platesare providedin the`deck and dual kin osts are-fused in veach truss,"one 'foreach i alf'of.the iloat, to

p ermit lfabrication of each' float elementas a rigidA self-containedstructure. ...These kingposts are inclinedand permanently secured-attheir upper ends to one side of theV deck opcnmgw ich is thenfree ofixed obstructions. The central closing ties between the upper endsof'thekingposts on each truss are formed as detachable tension links,one or more of'vvhieh may be readily removed should they interferewiththe desired aeces sibility. With the beltframe system of deck stif'enersof the prior-art, involving continullO .frames are often formed integralwith the ous frames extending across the deck openings, theaccessibility is impaired, a condition which it is one of vention toavoid.

In the usual belt-frame type of construction the frames .(when securedto longituditlebts'ide of which the skin plates are conformed, withtheresult that the rivets of the plates"4 last applied are accessibleonly through the usually small, hand holes. ,These floor beams byHanging over metal sheets tol form a ring of the desired profile whichusul-uy Valefl'l. frame to frame necessitating a large number ofcostlyoperations with Y relatively expensive forms or dies. vIn thepresent' invention, on the contrary,A the straight floor beams arefabricated separately from the deck frames or stifleners which areconstructed on' the system disclosed in my co-pending applicationhereinafter to be mentioned whereby these members are made stationprofiles and the plates are The internal structure is then' up in randomlengths which are easily Amanually conformable to any desired curvatureof plate and which form a rigid structure only after securing to theplate.

Accordingly, in the present system of float construction skeleten formsorr matrices representing each halfof the door are made up, preferablyof boards cut to the s ecified tted to these forms. fitted and rivetedto the plates and on securing the trussed kingposts and ties each openhalfv becomes` a rigid yself-contained structure ada itedto be securedto its companion lialf.- Since .all bracing is'commonly confined to theinside of the ioat,'which is usually too small to accommodate'workers,the provisions of this invention which permit of Ao ien-sidedfabrication rendering all connccv tions accessible for rivet workingwill greatly reduce costs and liability to faulty r forms `locatedworkmanship or incom lete inspection. Further,- by employing s eletnassembly mechanical riveting maybe used on account of the :open-sidedconstruction.

The water-tight Abulkheads lap .vertically amidships, thejoiitterminating at the' top of the cellular keel. Each half of the bulkheadis permanently secured to the associated keelson-side before the; halvesare brought together all the riveting being then readily. accessible;The new hollow keelson construction avoids bulkhead joint rivets be?ylow the keelson top where theywould bel in. accessible onaccount of theadjacent floor beams. j

Rivcted connections have been used for conveniencein terminology intheforegoing, [but any practicable fastenin f means may-tbe M usedwithout. departing rom the spirit. of

the objects of this ina 'dship step.

intermediate the frames `this invention. Also by way .of

illustration,l 'two sections conveniently referred to as halves havebeen iused, but

the assembly of the larger oats from any convenientenumber ofprefabricated sections is rendered practicable by the s ecial newconstructions of this invention w ichis not` specifically llimited to atwo-part construe.

arrows. l e

Figure 2 is a fragmentaryv view' showing the two halves in theirassembledrelation.

Figure 3 is a fragmentary longitudinal `sectiontaken on the line 34.-8of Fig. 2' and discloses the special construction of the iure- 4' is adiagrammaticv of a oat or pontoon. l Figure 5 iena diagrammatic view ofthe parts shown in Fig.. 1. i

. Figure 6 is an end elevation showing one of the forms which constitutea matrix'with one half of the float supported therein. A

` With reference to Figs. 1 and 2.I there is shown the two half portionsof a fioat, formside elevation `ed substai'itialyr alike inwliieh 10designates the curved outer shell or skinm'f'oi'ming'the sides and deckof the float and which is stiffened b a plurality'of longitudinallyspaced apart racing members 11 lpreferably formed in the manner asdisclosed -in the copending application of Roland Chilton, Ser. No.14,291", tiled March 9, 1925. To the lower edge of the skin 10 there issecured in any suitable manner, the Hoor plates 12 which are stifened4by a plurality of longitudifnally spaced apart beams 13 connecting withthe bracing 4members 11 and having upper and lower ianges,the latterbeing secured to the floor longitudinal am 14`substantial1y U-sliapeclin cross section`issecured to the upper edge of the skin 10 and isengaged by the ends of the bracing members'll.

To the inner ends of the floor `beams 13 pates by rivets as shown. A

on each'half of the fioat there is secured one side of the hollowkeelson 15 provided with flanges laadapted. to lap one another and to besecured together by therivets 1.55.' *ln this hollow keelson there isdisposed the-keel 16 secured in a removable mannerby the bolts 16. e

Kingposts 17 and cooperating tensioni `members 18 are `secured at theends of cer '1,30'

i tain `of the .flo-or beams. A tie member 22vl through the openings 21.

Suitably spaced bulkeads 19 provide water-tight compartments within thefloat and are constructed so that the two halves of each bulkhead mayform a lap joint directly over the keel 16. The rivet holes 20 of eachhalf are. adapted to register so as' to permit the introduction` of thevrivets openings 21.

therethrough in the iinal assembly, access for which is readily hadthrough' the upper .The tension links 22 are formed ottwo spaced apartmembers having a block 23 secured therebetween. These links are attachedto either side of the upper portionof the kingposts 17 by the bolts 24.

Suitable cover plates 25 having gaskets Iof yieldable material 26 areprovided to form a water-tight closure for vthe openings 21 when the twohalves of the iioathave been V brought together and fully secured.\These screws 25 which blocks 23. With reference to Fig. 5 there isindicated .cover plates 25 are Afastened down by the enter tapped holesin the by the arrows the direction in which the `forces are applied tothe structure by the struts 27 and the water 28. .This figure alsoindicates the nature of the stresses which the .various truss memberresist.

Fi 6 discloses the manner or method of formlng the individual halfortions of the lfloat in whicha number of re atively narrow forms orboards 29 are set u in spaced apart relation upon aoor or ot er base.These boards have been cut out as shown so as to form a templet ormatrixfor one half of the curvature for ,the bending of 'the' plates.

The beams `13, braces 11, `king posts 17,l

and in fact all of the'p'arts that go to make up each- -half'of afloatare applied and riveted in the form, the spacing of the boards 29 beingsuch as to'provide exterior access f to the plates to be riveted.Complete access to the interior is'affo'rdedI by the open condition of'the individual half portions of With reference to .3, 30l ldesignateslthe amidships step 'hereinbefore referred.,` to', i-n which. the afterbottom or loor plates' 12 are carried forward over the step and trenddownwardly to form a lapjoint with transverse to a'A relativelythickplate 32 interposed bei senseo tween the forward and after bottom platesat the lap joint.

While we' have shown and described and have pointed out in the annexedclaims certain novel features of our invention, it will beunderstoodthat variousv omissions, substitutions and changes in form anddetail of the device illustrated and in its operation may be made bythose skilled in the art without departing from the spirit of theinvention.

Having thus described our invention, we claim l 1. In a float, deckplates on either side of centrallongitudinal openings, a hollow keelsonincluding two side members, floor plates and beams secured to respectivekeelson sides, means for securing thekeelson sides together and means.for covering the deck openings. f'

`2. In a float, two longitudinally joinable halves each constituting afabricated unit comprising skin plating and a keelson meinber securedthereto,-means 4 for uniting the halvesby securing the keelson memberstogether and means for covering an opening between the upper plates ofthe two halves.

3. In a Heat structure, a central keelson having two side members eachvfabricated into one side of the float structure, and

means for uniting the keelson sides ,aften such fabrication.`

4.- A hull structure comprising two longitudinal halves adaptedforindividual fabrication and each includin a deck portion, a v

bottom portion anda eelson portion in combination with means :forconnecting the gi and keelson portions to form a closed 1 5. A floatcomprising two pre-fabricated jilongitu'dinal portions each includingskin plates, longitudinal lkeel halves and bulkead halves, and means foreonneetin the skin plating, the keel halves and theA ulkhead halves-.toform a closed structure havoat'and have been provided with the properbottom and having two side members overvlappmgat the top, bottom .platesvsecured to each side member, means for securingthe side memberstogether, and a keel piecenl sorted inthe hollow keelsonl and projectingdownwardly therefrom. f

7.- A keelson comprising, two longitudinal halves having 'substanti allyvertical portions v.spaced apart when in assembled relaf.t ion,j anupper flange on. one half adapted on assembly -to lap a correspondingvlange on 'the' other half, an outwardly turned flange on each half, incombination with' bottom Hang@ 8. In a float having bottom plates, ahollow keelson comprising spaced apart sides,

.Jplates secured l to each last said parts together.

each fabricated into a side portion of the bottom plates and means foruniting the keelson sides to assemble the float sides after memberfabricated into each float part,

bulkhead parts'in each float joined to the associated keelson sides incombination with jointing means between the bulkhead. "and keelson partsadapted to secure the float 12. In a float having a keel, a trussedframe comprising a pair of floor beams each having one end secured to aside of the keel and the other lend to the sides of the float, akingpost secured at the keel end of each beam, tension members tying thekingposts to the outboard ends of the beams and a connection between'the kingposts `and the top of the float.

13. In a float having a keel and side and deck plating, a trussed framecomprising floor beams secured between the keel-and the side plating,kingpost means secured at the keel ends of the beams, tie membersconnecting the kingpost means to the outboard end of the beams, saidkingpost means connected to the deck.

14. In a pontoon having a central deck opening and a keel, a trussedframe comprising kingposts secured on either side oi the keel andextending to either side of the deck opening, beams secui'ed at thekingposts to each side of the keel 'and to the sides of the pontoon,tiemeans connecting the upper ends vof the kingposts to the outboardends of the beams;A

15. Ina pontoon having a-l central deck sides of the pontoon, tie meansconnecting the upper ends of the kingposts together and to the outboardends of the beams, the xtie means between the kingposts being readilydetachable to cleartheopening of obstructions. y

16. The method of fabricating a lloat which consists in setting upskcletonforms vappropriate to each half profile of the float,

conforming skin plating to said forms, securing internal bracing to saidplates with the halves Iin open condition, and then assembling thehalves together to l'orm a closed float.

17. The method of fabricating a pontoon which consists in setting upskeleton forms defining the shape of each half of the pontoon,conforming the plates tothe said forms, fabricating keelson sides andsuitable bracing linto the skin plates with the halves inV openycondition, and then assemblying the halves together to form a closedpontoon.

18. In a float having. after bottom plates disposed higher than theforward plates to form a step, an after plate continued forL wardly overthe step and tending downward to connect with the forward plate ahead ofthe step and means for holding the end ofv the forward plate in spacedapart. relation to the after plate at the step.

= 19. In a pontoon having a step, a forward plate forming the bottom ofsaid step, a cross beam forming the face of the step, ali-after platesecured to thetop of the cross 'i beam and Vcontinuing forwardly thereofand downwardly therefrom to an 4attachment with the bottom plate`aheadof the step.

` 20. A step construction for a pontoon comprising a cross beam definingvthe depth ot the step, a bottom plate extending forwardly of the crossbeam and attached to the bottom thereof, anafter plate securedintermediate its ends to the top of the cross beam and extendingforwardly thereof to a point 'of attachment with the bottom plate.

21. A step structure for a hydroplane hull comprising a triangularsectioned box disposed atliwartships and having a substantiallyhorizontal face defined by the bottom plates, a substantiallyverticalside defining the face of `the step and a sloping top formed bythe after plates of the hull eX:

ment with the bottom plate.

Signed at Keyport in the county of Mon' mouth 'and State of New Jerseythis 13th day of March, A. I). 1925.V

ROLAND CHILTON. FRANK A. HAYES.

v tending forwardly of the step to an engagel

